This study describes the development and use of a mathematical model that will enable mine operators to
minimise the costs of electricity consumed by the ventilation and refrigeration systems used for
environmental control in deep mines.
This model was calibrated and tested by using actual data from a gold mine near Welkom in South
Africa. In a first simulation, the mine's current practice of controlling conditions to a wet bulb
temperature (Twb) of 25S°C, was optimised. The model demonstrated that this environmental condition
could be sustained at lower electricity consumption. In so doing, the mine realised a saving of 30 000
kWh per day. The energy saving and load management led to a cost saving of R 1.5 million per year.
However, a better indicator of environmental conditions is the Air Cooling Power index, (ACP).
Research has shown that for hard physical work in hot conditions workers need an ACP of 300 w/m2. It
was found that the case study mine actually supplied their workplace with a cooling capacity of 422
w/m2. The new model optimised the refrigeration and ventilation systems in such a manner that the
workers were supplied with exactly 300 w/m2, no more and no less. It was found that by doing this, an
electricity saving of 57 600 kWh per day could be realised when compared with the current mine
practices. The energy saving and load management led to a potential cost saving of R 2.55 million per
year. (Certain capital costs, such as for variable speed drives may have to be incurred to realise these
savings.)
The new model could be further extended to take advantage of the new Real Time Price offerings from
Eskom It will be able to identify an operating point for the refrigeration and ventilation systems to
supply 300 w/m2 for the workers, in real time, at the lowest electricity cost. / Thesis (Ph.D. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2004.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:nwu/oai:dspace.nwu.ac.za:10394/339 |
| Date | January 2003 |
| Creators | Swart, Christopher |
| Publisher | North-West University |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
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